Modification And Application Of Silk Based On Dopamine Rapid Polymerization

Silk is a natural protein fiber,widely used in textiles and biomedical materials.In order to further impart and improve the properties of silk fabric,they need to be modified.With the people's emphasis on the concept of ecological dyeing and finishing,dopamine,which is the equivalent of natural dyes,has attracted attention due to its unique role in material modification and functional textile preparation.In this paper,dopamine was rapidly oxidized polymerized and deposited on the surface of the fabric to obtain preliminary modification of the fabric.Fe2+ was further mineralized on the surface of the polydopamine(PDA)coating to prepare a PDA-modified multifunctional silk fabric.In addition,the dopamine mineralized iron is supported on the waste silk as a catalyst to efficiently degrade the dye and increase the added value of the waste silk.The specific research contents and results are as follows:The one-bath method was used to modify the silk fabric by rapid oxidative polymerization of dopamine.The factors such as the addition time and concentration of oxidant(Ox),the concentration of Fe3+,and the processing time were discussed.Ox was added at 10 min of reaction,the concentrations of Ox and Fe3+ was 9 mmol/L and 2 mmol/L,respectively.When reacted for 50 min,the fabric had a higher color depth value.This method can greatly shorten the polymerization reaction time of dopamine.The modified fabric had good color fastness,certain hydrophobic and ultraviolet resistance properties.PDA can adsorb metal ions through chelation and generate corresponding minerals in situ.XRD and TEM test results showed that the mineralization was a mixture of hydroxylated iron.When the Fe2+ concentration was 40 mmol/L and reaction time was 24 h,the static water contact angle(CA)of the modified fabric was 156.6°,the sliding angle(SA)was about 8°,the vertical burning damage length was 11.2cm,and the ultraviolet protection factor(UPF)was 38.77.Fe2+ mineralized on the surface of the PDA coating,forming a micro-nano rough structure similar to the surface of lotus leaves,giving the fabric superhydrophobic properties.PDA coating could improve the carbonization performance of the fabric during the combustion process.When heated,the iron hydroxide released flame-resistant gases to prevent the fabric from further burning.PDA is a melanin-like substance with good UV resistance.Super-adhesive property of PDA similar to marine mussels endows the prepared silk fabrics with good functional stability after washing and rubbing.A dopamine mineralized iron/H2O2 Fenton-like system was constructed by loading PDA mineralized iron onto waste silk as a catalyst,and its degradation of methylene blue and reactive orange GRN simulated dye wastewater was studied.The results showed that the self-made catalyst system had a degradation rate of more than 95%for methylene blue and active orange GRN.In addition,the addition of inorganic salts NaCl and Na2SO4 in the dyeing solution reduced the degradation efficiency of the dye slightly.After 4 times continuous degradations,the degradation efficiency of the catalyst for methylene blue and active orange GRN was reduced.